ACT 38 Pennsylvania Nutrient Management Program Changes and the Impact on Biosolids Land Application

ISSUE: On October 29, 2011, the Pennsylvania Department of Environmental Protection published guidelines for manure management which introduced changes to the specifications regarding nutrient management of manure and biosolids application to farmland. (1) The changes to the allowed phosphorus levels (the Phosphorus Index, or P Index) will have an effect on the future feasibility of using biosolids on some types of farms, especially those with livestock. (2)

BACKGROUND: Comprehensive Nutrient Management Plans (CNMPs) are site-specific conservation plans unique to livestock operations.   Besides addressing natural resource concerns related to soil erosion, manure and disposal of organic by-products, these plans incorporate guidelines on best management practices (BMPs) to manage the use of nutrients, such as nitrogen and phosphorus, for crop production, and water quality protection.


Penn State’s College of Agricultural Sciences Cooperative Extension Service fact sheet on “The Use of Biosolids in Crop Production” highlights the concern about fertilizer leaching or runoff, primarily of nitrate as well as soluble and sediment-bound phosphate. These risks can be mitigated by following BMPs which manage nutrients to protect surface and ground water while taking into account applicable nutrient requirements for crop utilization. However, as the fact sheet explains, applying either manure or biosolids based on a crop’s nitrogen needs, will also add an excess of four to five times more P than is needed by the crop. Continued annual application of biosolids and/or manure will then result in a buildup of P in the soil which increases the risk of the P being eroded or dissolved and running off into streams and rivers.

The P Index was developed as a field evaluation tool to monitor areas that are prone to phosphorus loss to bodies of water. It takes into account fertilizer, manure, and biosolids application rates and methods, and P source coefficients, as well as erosion, runoff, drainage, distance to open water and on-site management practices. Farmers are required to first develop a nitrogen-based nutrient management plan for crop management and then evaluate that plan using the P Index. (2)

The new regulations may create a problem for those livestock farmers who are applying manure as well as biosolids. If the application rates are restricted, they will be obliged to give priority to manure application in order to manage and dispose of it. They may not be able then to accept biosolids in addition, due to the possibility of increased P levels.


CONSEQUENCES/ALTERNATIVES: Wastewater treatment plants using land application to manage biosolids will need to explore ways to comply with the new P requirements if they hope to continue to supply biosolids to farms. If those plants who produce biosolids for land application continue with “business as usual” under the new regulations, they may now find that agricultural farms without livestock will be better suited to biosolids use and more inclined to need the nutrients in biosolids. But even those farms using heat dried biosolids - if they have livestock or are importing manure - must track nutrient levels from fertilizer, manure, and biosolids applications and will be subject to the more stringent P regulations. Other means of equalizing the N:P ratio on croplands where biosolids are applied may include processes to strip P from incoming wastewater at the plant (3), or to add N fertilizer to biosolids before land applying. Farmers, too, must change some of their practices. For example, biosolids and manure application BMPs include land application setbacks to protect waterways from nutrient runoff. Some suggest that farmers also rotate their crops with those that take up high levels of P so that the excess will be removed from the soil. However, Dr. Doug Beegle, of Penn State University, has a dim view of the effectiveness of this method, saying it will take decades to reduce soil P once the concentration is 200 ppm. (4)


Certified Nutrient Management Specialists can help farmers plan the safest and best use of biosolids, manure, and fertilizer.  This is important because, when a farmer is using manure, he must have a manure management plan, and if the farmer wants to use biosolids, the plan must show that there is not a surplus of nitrogen or phosphorus for the fields. It must provide guidelines for managing nutrients for crop production as well as environmental protection. As requirements become more stringent, such specialists will prove invaluable to farmers who wish to land apply biosolids.


CONCLUSIONS: While a number of methods have been suggested for phosphorus removal or mitigation, there are two other alternative management options that show promise. It may be worth the effort for wastewater treatment plants to offer biosolids for use in reclamation areas where soils are depleted of phosphorus (e.g. minelands where topsoil has been removed and the soil quality is very poor). And it may also be feasible to reduce the concentration of phosphorus in biosolids by recovery and marketing of phosphorus at the wastewater treatment plant. The recovered P could then be marketed as a fertilizer. After all, the worlds’ supply of phosphorus from mining is limited.

To highlight this latter effort, the Water Environment Research Foundation (WERF) will be sponsoring research on Nutrient Recovery in the Global Water Industry”. WERF’s statement of the issue gives a nice summary of the status of the technologies used to recover P: Nutrient recovery, particularly the recovery of phosphorus (P) has been studied and reported in both the scientific literature and is now commercially available at some wastewater treatment facilities. Processes for industrial recovery of P by struvite precipitation have also been available for almost a decade. Much of the work has focused on the wastewater sidestream (e.g., centrate from dewatering processes, anaerobic digester supernatants, etc); however, not as much has been completed and/or published or demonstrated on P recovery from the mainstream wastewater or from biosolids. In addition, adoption of the technology(ies) by the wastewater sector is somewhat limited. The industry is in need of a thorough analysis of best options and guidance for the selection and implementation of viable technologies and processes for sustainable nutrient recovery. “

SUMMARY: The new P Index regulations will no doubt have an impact on biosolids recycling programs in Pennsylvania, presenting a challenge for wastewater treatment plants and farmers alike.

(1) Per the Penn State Cooperative Service, these guidelines can be found in the revised Pennsylvania Department of Environmental Protection Manure Management Manual. The manual and the accompanying Manure Management Plan Workbook can be accessed and downloaded from DEP’s Manure Management page ( A Manure Management Manual Program page has been added to the Act 38 Pennsylvania Nutrient Management Program website (


(2) Per the Penn State College of Agricultural Sciences fact sheet on Water Quality and Phosphorus, “Increased attention has focused on phosphorus (P) management due to water quality concerns resulting from eutrophication. In freshwater systems, elevated P inputs can lead to accelerated eutrophication and degraded water quality. Despite water quality concerns, adequate levels of soil P must be maintained to promote optimal crop production. Therefore, management options for P must be flexible in order to address agronomic concerns while providing water quality protection.”


(3) Brandt, R.C. and H.A. Elliott. 2009. Sustaining biosolids recycling under phosphorus-based nutrient management. Water Practice. 3(1):1-14.

(4) 200 ppm P in soil is a trigger point at which the phosphorus index must be calculated to determine if manure and biosolids loading rates would be limited to the crops’ P uptake rate.


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